Theft-preventive attachment for locks

ABSTRACT

A theft-preventive attachment for locks of the rim type which are mounted on sliding doors and movable into engagement with a keeper mounted on the door jamb, both lock and keeper having interfitting bolting fingers or projections. The attachment is in the form of a tube which fits snugly around the projections on the lock body and is carried thereby toward the keeper as the door is slid closed. When the door is closed and the lock bolted, the tube encloses the interfitting bolting projections so that they are not exposed or accessible from the front of the lock and cannot be tampered with. The front wall of the attachment also extends beyond the tube and covers over the mounting bolts of the lock body.

United States Patent 11 1 Greene, deceased et al.

[ 1 May 8, 1973 FOR LOCKS Inventors: Oscar Greene, deceased; late of 115 E. 86th St., New York, N.Y. 10028 Robert S. Greene, executor; Robert L. Pelz, executor, 230 Park Ave., New York, N.Y. 10017 Filed: Ma 10, 1971 Appl. No.: 141,572

us. or ..70/97, 292/346 Int. Cl. ..E05b 65/08 Field of Search ..7o/9s-10o, 416-418;

11/1929 Great Britain ..70/4 1 6 732,594 6/1955 Great Britain "70/418 Primary Examiner-Joseph H. M cGlynn Attorney-Edward F. Levy ABSTRACT A theft-preventive attachment for locks of the rim type which are mounted on sliding doors and movable into engagement with a keeper mounted on the door jamb, both look and keeper having inter-fitting bolting fingers or projections. The'attachment is in the form of a tube which fits snugly around the projections on the lock body and is carried thereby toward the keeper as the door is slid closed. When the door is closed and the lock bolted, the tube encloses the interfitting bolting projections so that they are not exposed oraccessible from the front-of the lock and cannot be tampered with. The front wall of the attachment also extends beyond the tube and covers over the mounting bolts of the lock body.

4 Claims, 4 Drawing; Figures Patented May '8, 1973 3,731,506

7 5 4 4% v I In? f6 INVENTOR. O R GREENE ATTORNEY 1 THEFT-PREVENTIVE ATTACHMENT FOR LOCKS The present invention relates to an attachment for a rim type lock which prevents access to the operative portions of the lock when the latter is in bolted condition.

The attachment is devised for use with dead-bolt rim type locks which are mounted on sliding doors of elevators, warehouses and the like. In such lock the lock body containing the cylinder, bolt and keyway, is mounted on the outer surface of the sliding door and is moved with the door into engagement with a keeper mounted on the doorjamb. The lock body has a plurality of projections or fingers which interfit with corresponding fingers on the keeper, and when the cylinder is locked, bolt pins in the lock body fingers move downwardly through apertures in the keeper fingers to provide the bolting action.

While locks of this type are difficult to pick, they may be forcibly broken and opened without much difficulty. Since the interfitting fingers and bolt pins are fully exposed and accessible at the front of the lock, a thief need only insert a chisel between the fingers and shear off the bolt pins. y

In accordance with the present invention, there is provided a theft-preventive attachment for locks of the aforementioned type comprising a tubular cover which is sized to enclose the interfitting fingers when the lock body is in engagement with the keeper, thereby covering over the vulnerable lock parts which are normally exposed for tampering. The tubular cover is initially inserted over the projecting fingers of the lock body and is movable with the latter into a position in which it also covers over the keeper fingers when the door is slid to closed position. The front wall of the attachment is also made of sufficient length to project beyond the tubular portion of the attachment and overlie the front surface of the lock body, covering over the mounting bolts of I the lock body.

It is an object of the present invention to provide a theft-preventive attachment of the character described which is of extremely simple form and may be produced economically.

Another object of the invention is the provision of a theft-preventive attachment of the character described which may be quickly and easily mounted on the lock by merely slipping it over the lock body fingers, and which automatically is brought to proper operative position when the sliding door is closed, and is secured in operative position when the lock is bolted.

Additional objects and advantages of the invention will become apparent during the course of the following specification when taken in connection with the accompanying drawings, in which:

FIG. I is a top plan view ofa lock in bolted condition with the theft-preventive attachment of the invention mounted thereon, with portions broken away and shown in section to reveal constructional detail;

FIG. 2 is a front plan view of the lock shown in FIG.

FIG. 3 is a section taken along line 3-3 of FIG. 2; and

FIG. 4 is a perspective view of the theft-preventive attachment of the invention.

Referring in detail to the drawings, there is shown in FIGS. 1 to 3 a lock of the type for which the theft preventive attachment of the present invention is devised. The lock 10 is a conventional and well-known dead-bolt lock of the rim type which is especially made for mounting on the outer surfaces of sliding doors used in elevators, warehouses or the like.

The lock 10 has a flat body portion 12 which is secured to the outer surface of a sliding door 14 by a plurality of screws or bolts 16. Projecting from the body portion 12 is a housing 18 for a cylinder 20 containing a keyway 22. The lock 10 operates in the usual manner; when the proper key is inserted in the keyway 10, the cylinder 20 may be rotated to actuate a sliding bolt (not shown) within the body portion 12 and thereby cause vertical movement of a pair of pins 24, 26 which are slidably mounted in respective fingers 28, 30 which project from the body portion 12. The lock body portion is mounted in such position on the door 14 that the fingers 28 and 30, as well as an additional finger 32, project beyond the door edge 34.

The lock 10 also includes a keeper 36 which is secured to the door jamb 38 in position to cooperate with the lock body 12. The keeper-36 has a pair of projecting fingers 40 and 42 which register with the spaces between the fingers 28, 30 and 32. When the door 14 is slid to itsclosed position, the keeper fingers 40 and 42 enter the spaces between the body portion fingers 28, 30 and 32. When a key is inserted and the lock actuated, the pins 24 and 26 are lowered and enter apertures in the respective keeper fingers 40 and 42 to provide the locking action.

It will be seen in FIG. 3 that while the lock body portion 12 has a flat rear wall '44 which lies, flush against the surface of the door 14, the fingers 28, 30 and 32 are spaced outwardly from the plane of the door surface by a distance of approximately V4 inch, a shoulder 46 being defined between the fingers and the rear wall 44. Similarly, the fingers 40 and 42 of keeper 36 are spaced forwardly of the surface of door jamb 38.

In the'bolted position of the lock 10 shown in FIG. 2,

the keeper fingers 40 and 42 between the fingers 28, 30 and 32 are exposed for access at the outside of the door 14, and the heads of bolts 16 are also exposed. Portions of the pin 24 between the interfittin'g fingers (shown in solid line in FIG. 2) are similarly exposed. In theft attempts, therefore, it is a rather easy matter to break open the lock by inserting a chisel or similar tool in the spaces between the interfitting fingers and simply shearing off the bolt. If necessary, the keeper fingers 40 and 42 may also be cut off, but with somewhat more difficulty. In addition, while the mounting bolts 16 are normally secured against rotation after the lock has been mounted, it is possible for the thief to drill out the bolts from the front of the lock and remove the lock body 12 from the door 14.

To make such lock tampering efforts more difficult, if not impossible, the present invention contemplates the provision of an auxiliary theft-preventive attachment in the nature of a protective cover 50 which, in the closed position of the lock parts, covers over the interfitting fingers.

As shown in FIG. 4, the cover 50 is in the form of a flat tube having side walls 52 and 54, a rear wall 56, and a front wall 58. The rear wall 56 is of considerably lesser length than the front wall 58 and side walls 52, 54, and forms with the latter a rectangular tubular portion having a cross-sectional area generally conforming to and slightly larger than the cross-sectional area of the lock body in the region of the fingers 28, 30 and 32. When the cover 50 is inserted upon'the lock body 12, the rectangular tubular portion fits snugly around the three fingers 28, 30 and 32 and the inner edge 60 of rear wall 56 engages the shoulder 46 of body portion 12, as indicated in FIG. 1, to stop further inserting movement.

The cover 50 may be placed on the lock body portion 12, in the manner just described, immediately before the lock is to be bolted, or it may be left permanently in mounted position without interfering in any way with the operation of the lock. In any even, when the cover 50 is so mounted and the door 14 is closed by sliding it horizontally in the direction of arrow 62 (FIG. 1) into abutment with the door jamb 38, the fingers 28, 30 and 32 are moved into interfitting relationship with the keeper fingrs 40 and 42, and the cover 50 is carried with the lock body 12 to an operative position in which the rectangular tubular portion encloses the keeper fingers as well as the body portion fingers. This operative position is shown in FIGS. 1, 2 and 3.

The cover 50 is so dimensioned that in the aforementioned operative position, the inner edge 60 of rear wall 58 engages or is closely spaced from the shoulder 46 on body portion 12, while he outer edge 64 of rear wall 58 engages or is closely spaced from the body of keeper 36, as shown in FIG. 1. The cover 50 is thus restrained from movement in either direction out of its operative position, and when the lock is bolted, the cover 50 is held in its operative position in which the interfitting fingers 28, 30, 32, 40 and 42 are completely enclosed and covered over by the portions of walls 52, 54, 56 and 58 which define the rectangular tube. In particular, the front wall 58 covers over the interfitting fingers so that they are no longer exposed and accessible from the front of the lock.

The cover 50 is made of heavy gauge metal such as bronze or steel, and the walls thereof are made as thick as possible for maximum strength, the limit of such thickness being only determined by the necessity for the rear wall 56 tofit easily between the door and jamb surfaces and the fingers.

As previously indicated, the front wall 58 and the side walls 52, 54 are made appreciably longer than the rear wall 56 so that portions of these walls extend well beyond the rectangular portion defined by rear wall 56 and form an inner U-shaped section shown in FIG. 4. These extension wall portions are made sufficiently long that in the mounted, operative position of the cover 50, the front wall 58 overlies the front face of the body portion 12 and covers over the pair of bolts 16 which are adjacent the fingers, as shown in FIG. I. If desired, the front wall 58 may be made even longer so that it also covers over the other pair of bolts 16.

It will be apparent that when the lock 10 is bolted with the cover 50 in mounted, operative position, the front wall 58 covers over the interfitting fingers and the mounting screws, and the cover must be forcibly broken open for removal, which would be extremely difficult task. The presence of the cover alone would tend to discourage a thief from attempting to tamper with the lock.

While a preferred embodiment of the invention has been shown and described herein, it is obvious that numerous omissions, changes and additions may be made in such embodiment without departing from the spirit and scope of the invention.

What is claimed is:

l. A theft-preventive attachment for use with a rim type lock having a lock body mounted on a sliding door for movement parallel to the plane of the door toward and away from an engaged position with a keeper mounted on the door jamb, said lock body having laterally-projecting bolting fingers which interfit with laterally-projecting fingers on the keeper when the lock body is in said engaged position; said theft-preventive attachment comprising a cover made of heavy-gauge metal and including a tubular portion of rectangular cross section sized to be inserted upon the bolting fingers of said lock body when the latter is out of its engaged position with said keeper, said tubular portion being of sufficient length that when said lock body is moved to its engaged position with said keeper, the tubular portion is brought to an operative position enclosing said interfitting fingers and the front wall of said tubular portion overlies said interfitting fingers to prevent exposure thereof from the front of the lock, said cover having a pair of side walls, a rear wall and a front wall, said front wall and side walls being substantially longer than said rear wall and defining with the latter the rectangular cross section of said tubular portion.

2. A theft-preventive lock attachment according to claim 1 in which said front and side walls have extension portions projecting laterally beyond said tubular portion, said extension portions being sufficiently long that when said tubular portion is in its operative position, the extension portion of the front wall overlies the front surface of the lock body and shields said surface from exposure at the front of the lock.

3. A theft-preventive lock attachment according to claim 2 in which said tubular portion is sized to fit snugly about the fingers of said lock body.

4. A theft-preventive lock attachment according to claim 2 in which said rear wall is made of such length that in the operative position of said tubular portion one end edge of the rear wall is proximate to a portion of the lock body and the other end edge of the rear wall is proximate to a portion of said keeper, whereby said tubular portion is restrained from movement out of its operative position. 

1. A theft-preventive attachment for use with a rim type lock having a lock body mounted on a sliding door for movement parallel to the plane of the door toward and away from an engaged position with a keeper mounted on the door jamb, said lock body having laterally-projecting bolting fingers which interfit with laterally-projecting fingers on the keeper when the lock body is in said engaged position; said theft-preventive attachment comprising a cover made of heavy-gauge metal and including a tubular portion of rectangular cross Section sized to be inserted upon the bolting fingers of said lock body when the latter is out of its engaged position with said keeper, said tubular portion being of sufficient length that when said lock body is moved to its engaged position with said keeper, the tubular portion is brought to an operative position enclosing said interfitting fingers and the front wall of said tubular portion overlies said interfitting fingers to prevent exposure thereof from the front of the lock, said cover having a pair of side walls, a rear wall and a front wall, said front wall and side walls being substantially longer than said rear wall and defining with the latter the rectangular cross section of said tubular portion.
 2. A theft-preventive lock attachment according to claim 1 in which said front and side walls have extension portions projecting laterally beyond said tubular portion, said extension portions being sufficiently long that when said tubular portion is in its operative position, the extension portion of the front wall overlies the front surface of the lock body and shields said surface from exposure at the front of the lock.
 3. A theft-preventive lock attachment according to claim 2 in which said tubular portion is sized to fit snugly about the fingers of said lock body.
 4. A theft-preventive lock attachment according to claim 2 in which said rear wall is made of such length that in the operative position of said tubular portion one end edge of the rear wall is proximate to a portion of the lock body and the other end edge of the rear wall is proximate to a portion of said keeper, whereby said tubular portion is restrained from movement out of its operative position. 